HD 142022
Binary star system in the constellation Octans
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HD 142022 is a binary star[9] system located in the southernmost constellation of Octans. It is too faint to be visible to the naked eye, having an apparent visual magnitude of 7.70.[3] The distance to this system is 112 light-years (34 parsecs) based on parallax, but it is drifting closer to the Sun with a radial velocity of −10 km/s.[2]
| Observation data Epoch J2000 Equinox ICRS | |
|---|---|
| Constellation | Octans[1] |
| Right ascension | 16h 10m 15.02895s[2] |
| Declination | −84° 13′ 53.8108″[2] |
| Apparent magnitude (V) | 7.70[3] + 11.19[4] |
| Characteristics | |
| Spectral type | G9IV-V[5] + M1V[4] |
| B−V color index | 0.79±0.01[3] |
| Astrometry | |
| Radial velocity (Rv) | −9.96±0.13[2] km/s |
| Proper motion (μ) | RA: −337.270 mas/yr[2] Dec.: −31.386 mas/yr[2] |
| Parallax (π) | 29.1991±0.0172 mas[2] |
| Distance | 111.70 ± 0.07 ly (34.25 ± 0.02 pc) |
| Absolute magnitude (MV) | 5.02[3] |
| Details[6][4] | |
| A | |
| Mass | 0.972+0.036 −0.029 M☉ |
| Radius | 1.028+0.011 −0.012 R☉ |
| Luminosity | 0.886±0.001[7] L☉ |
| Surface gravity (log g) | 4.386±0.251 cgs |
| Temperature | 5,516±31 K |
| Metallicity [Fe/H] | 0.24±0.073 dex |
| Rotational velocity (v sin i) | 2.048±0.214 km/s |
| Age | 7.667+1.704 −1.764 Gyr |
| B | |
| Mass | 0.60±0.07 M☉ |
| Radius | 0.56±0.05 R☉ |
| Luminosity | 0.063±0.014 L☉ |
| Temperature | 3,892±95 K |
| Other designations | |
| CD−83°202, GC 21507, GJ 606.1, GJ 9536, HD 142022, HIP 79242, SAO 258738, LTT 6382, GCRV 65757[8] | |
| Database references | |
| SIMBAD | data |
The primary, designated component A, is an old,[9] Population I G-type star with a stellar classification of G9IV-V,[5] showing a spectrum with mixed traits of a main sequence and a subgiant star. It is an estimated 7.6 billion years old and is spinning with a projected rotational velocity of 2 km/s. The star has similar mass and dimensions as the Sun, but has a 55% higher metallicity.[6] It is radiating 89%[7] of the luminosity of the Sun from its photosphere at an effective temperature of 5516 K.[6]
The magnitude 11.19[4] companion has the designation LTT 6384 and appears gravitationally bound to the primary. The pair have an angular separation of 22 arcseconds, which corresponds to a projected separation of ~820 AU. The estimated semimajor axis of their orbit is 1,033 AU.[9] The secondary is a red dwarf star with a stellar classification of M1V.[4]
The primary star has a single known planetary companion, HD 142022 Ab, discovered in 2005.[9] In 2023, the inclination and true mass of HD 142022 Ab were determined via astrometry.[10]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (years) |
Eccentricity | Inclination (°) |
Radius |
|---|---|---|---|---|---|---|
| b | 4.51+0.91 −0.61 MJ |
2.939±0.062 | 5.297+0.082 −0.073 |
0.506+0.071 −0.06 |
71±13 or 109±13 | — |